CN211036177U

CN211036177U - Reverse lifting type single crystal furnace

Info

Publication number: CN211036177U
Application number: CN201921840402.7U
Authority: CN
Inventors: 王志磊; 张燕玲; 邢德春; 王志卿; 于彩凤
Original assignee: Jingchuang Mingsheng Electronic Technology Xianghe Co ltd
Current assignee: Jingchuang Mingsheng Electronic Technology Xianghe Co ltd
Priority date: 2019-10-30
Filing date: 2019-10-30
Publication date: 2020-07-17
Anticipated expiration: 2029-10-30

Abstract

The utility model provides a reverse lifting type single crystal furnace, which abandons the crystal growth mode of lifting seed crystal and realizes the reverse lifting effect through the descending of a driving crucible. Particularly, the seed crystal is fixed above the crucible, and the lower ends of the crucible and the graphite heater are supported by a lifting support; based on the structure, after the melting step is finished, the crucible is driven to descend to realize the relative distance between the crucible and the seed crystal, so that the growth of the single crystal along the lower end of the seed crystal is realized; on the basis, the utility model adds a limiting mechanism below the crucible and the graphite heater, and can limit the descending range of the crucible and the graphite heater. In addition, the utility model provides a concrete optional configuration of elevating system and graphite heater, wherein, elevating system drives the fore-set based on the lead screw principle, can realize its steady lift; the asbestos heater is formed by surrounding U-shaped metal plates into a cylinder structure, and can ensure that all directions can provide electric heating function.

Description

Reverse lifting type single crystal furnace

Technical Field

The utility model relates to a single crystal growing furnace technical field, concretely relates to reverse lift-draw formula single crystal growing furnace.

Background

The single crystal furnace is a device for melting polycrystalline materials such as polycrystalline silicon and the like by using a graphite heater in an inert gas (mainly nitrogen and helium) environment and growing dislocation-free single crystals by using a Czochralski method.

During the operation of the single crystal furnace, firstly, putting a high-purity polycrystalline silicon raw material into a high-purity quartz crucible, and melting the high-purity polycrystalline silicon raw material through high temperature generated by a graphite heater; then, slightly cooling the molten silicon liquid to generate a certain supercooling degree, inserting a silicon single crystal (called seed crystal) fixed on a seed crystal shaft into the surface of the melt, and slowly pulling the seed crystal upwards after the seed crystal is melted with the melt, so that the crystal can grow at the lower end of the seed crystal; then, controlling the seed crystal to grow a section of thin neck with the length of about 100mm and the diameter of 3-5 mm, and eliminating dislocation of atomic arrangement generated by strong thermal shock of the high-temperature solution to the seed crystal, wherein the process is seeding; then, amplifying the diameter of the crystal to the size required by the process, generally 75-300 mm, wherein the process is called shouldering; then, suddenly increasing the pulling speed to perform shoulder turning operation, so that the shoulder is approximately right-angled; then, performing an equal-diameter process, and growing a single crystal cylinder with a certain diameter and size by controlling the temperature of the thermal field and the crystal lifting speed; finally, when most of the silicon solution has been crystallized, the crystal is gradually shrunk to form a tail cone, which is called a tail process. Thus, a single crystal pulling process is substantially completed and can be removed after a certain amount of heat preservation and cooling.

Therefore, the preparation process of the monocrystalline silicon greatly depends on the monocrystalline furnace, and the performance of the monocrystalline furnace not only influences the processing efficiency, but also has important influence on the growth effect and the processing precision of the crystal. In a conventional single crystal furnace, the growth of the monocrystalline silicon is realized by driving the seed crystal to move upwards from the molten crystal by the pulling mechanism, and the seed crystal and the pulling head are in a driving connection relationship in the mode, so that the high requirement on a fit connection structure of the seed crystal and the pulling head is met; moreover, due to the nature of the natural rise of hot air, the heat load of the lifting mechanism above in this mode is large, which is not beneficial to prolonging the service life of the equipment.

Disclosure of Invention

The utility model aims to solve the technical problem of how to provide a single crystal furnace with a novel pulling mode.

The utility model also solves the technical problem of avoiding arranging a driving mechanism above the single crystal furnace.

In order to realize the technical purpose, the utility model adopts the following technical scheme:

a reverse pull-up type single crystal furnace comprises a furnace body, a graphite felt, a top column, a supporting platform, a graphite heater, a crucible, a fixed column, seed crystals, a base barrel, a supporting column and a limiting ring, wherein the graphite felt is fixedly connected to the inner wall of the furnace body; the furnace body is fixedly connected with a base barrel through a pillar, a limiting ring is fixedly connected to the bottom surface of the base barrel, and a top pillar penetrates through the limiting ring and the bottom surface of the base barrel.

Preferably, the lifting mechanism comprises an internal thread sleeve, a cylindrical part and a motor, wherein an external thread part is arranged on the outer wall of the lower part of the top column, the internal thread sleeve is screwed on the external thread part of the top column, the cylindrical part is fixedly connected to the lower end of the internal thread sleeve, and a main shaft of the motor is in transmission connection with the cylindrical part.

Preferably, the graphite heater comprises a plurality of U-shaped metal plates, annular hoops and electrodes, wherein the U-shaped metal plates surround to form a cylinder, the annular hoops are fixedly connected to the side wall of the cylinder, and the electrodes are respectively connected to two ends of each U-shaped metal plate.

Preferably, the fixed column and the seed crystal are both in a cylindrical shape, the axes of the fixed column and the seed crystal are mutually overlapped, and the lower end of the seed crystal is provided with a conical surface.

Preferably, the axis of the top column and the axis of the furnace body are overlapped; the diameter of the inner edge of the limiting ring is smaller than that of the outer edge of the support platform.

In the technical scheme, the furnace body is a shell structure of the single crystal furnace and is used for sealing a crucible, a heating mechanism and the like; the graphite felt plays roles in heat insulation and heat preservation; the upper end of the top column is provided with a support table, and the graphite heater and the crucible are positioned on the support table, so that the graphite heater and the crucible can be driven to move up and down along with the graphite heater and the crucible by the up-and-down movement of the top column; the support table is used for bearing the graphite heater and the crucible; the graphite heater has a heating function on the crucible inside, so that the polycrystalline silicon material in the crucible is heated and melted; the crucible is used for containing polycrystalline silicon materials and is used as a place for single crystal hot melting and growth; the fixed column is used for fixing the seed crystal and suspending the seed crystal above the crucible, when the materials in the crucible are melted completely, the crucible is driven to ascend, the lower end of the seed crystal is immersed in the materials, the crucible is driven to descend, the materials are far away from the seed crystal, and the materials grow along the lower end of the seed crystal in the process; the pillar is used for bearing a base section of thick bamboo, makes it be fixed in the saddle below, and a base section of thick bamboo is used for bearing the spacing ring, and the spacing ring is used for playing limiting displacement to the decline position of saddle, avoids it to descend too much.

In above technical scheme, the up-and-down motion of fore-set relies on furnace body below, independent elevating system realizes, the utility model discloses an optional configuration of this elevating system has further been given: the internal thread sleeve is in threaded connection with the lower portion of the top column, the cylindrical portion fixed with the internal thread sleeve is used for establishing a transmission connection relation with a motor, the transmission connection relation can be that a motor spindle directly drives the cylindrical portion through a coupler, and can also be in a conventional transmission mode such as gear transmission.

Furthermore, the utility model discloses an optional configuration of graphite heater is further given: the U-shaped metal plates are used for enclosing a cylinder shape to bear the crucible, electrodes at two ends of each U-shaped metal plate play an electric heating role, and the annular hoops positioned on the periphery of the cylinder shape are used for connecting the U-shaped metal plates to ensure the stability of the cylinder shape.

The utility model provides a reverse lifting type single crystal furnace, which abandons the crystal growth mode of lifting seed crystal and realizes the reverse lifting effect through the descending of a driving crucible. Particularly, the seed crystal is fixed above the crucible through the fixing column, and the lower ends of the crucible and the graphite heater are supported by the liftable support; based on the structure, after the melting step is finished, the crucible is driven to descend to realize the relative separation of the seed crystal and the crucible under the state that the seed crystal is fixed, thereby realizing the growth of the single crystal along the lower end of the seed crystal; on the basis, the utility model adds a limiting mechanism below the crucible and the graphite heater, and can limit the descending range of the crucible and the graphite heater. In addition, the utility model provides a concrete optional configuration of elevating system and graphite heater, wherein, elevating system drives the fore-set based on the lead screw principle, can realize its steady lift; the asbestos heater is formed by surrounding U-shaped metal plates into a cylinder structure, and can ensure that all directions can provide electric heating function.

Drawings

FIG. 1 is a schematic view of the structure of the vertical section inside the furnace body of the present invention;

FIG. 2 is a schematic view of a drive mechanism of the present invention;

FIG. 3 is a schematic structural view of a graphite heater according to the present invention;

in the figure:

1. furnace body 2, graphite felt 3, fore-set 4, saddle

5. Graphite heater 6, crucible 7, fixed column 8 and seed crystal

9. Base barrel 10, support 11, limiting ring 12 and internal thread sleeve

13. Cylindrical part 14, motor 15, U-shaped metal plate 16 and annular hoop

17. And an electrode.

Detailed Description

The following will describe in detail specific embodiments of the present invention. Well-known structures or functions may not be described in detail in the following embodiments in order to avoid unnecessarily obscuring the details. Approximating language, as used herein in the following examples, may be applied to identify quantitative representations that could permissibly vary in number without resulting in a change in the basic function. Unless defined otherwise, technical and scientific terms used in the following examples have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

Example 1

A reverse pull-up type single crystal furnace is shown in figure 1 and comprises a furnace body 1, a graphite felt 2, a top column 3, a support table 4, a graphite heater 5, a crucible 6, a fixed column 7, seed crystals 8, a base barrel 9, a support column 10 and a limiting ring 11, wherein the graphite felt 2 is fixedly connected to the inner wall of the furnace body 1, the top column 3 is inserted into the furnace body 1, the upper end of the top column 3 is positioned inside the furnace body 1, the lower end of the top column 3 is positioned below the furnace body 1, the lower end of the top column 3 is connected with a lifting mechanism, the support table 4 is fixedly connected to the upper end of the top column 3, the graphite heater 5 is fixedly connected to the support table 4, the crucible 6 is connected to the inside of the graphite heater 5, the fixed column 7 is fixedly connected to the upper end of the furnace body 1, the seed crystals 8 are fixedly connected to the lower end of the fixed column; a base cylinder 9 is fixedly connected to the inside of the furnace body 1 through a support column 10, a limit ring 11 is fixedly connected to the bottom surface of the base cylinder 9, and the top column 3 penetrates through the limit ring 11 and the bottom surface of the base cylinder 9.

The device has the following structural characteristics: the furnace body 1 is a shell structure of a single crystal furnace and is used for sealing a crucible 6, a heating mechanism and the like; the graphite felt 2 plays roles of heat insulation and heat preservation; the upper end of the top column 3 is provided with a support table 4, and the graphite heater 5 and the crucible 6 are positioned on the support table, so that the graphite heater 5 and the crucible 6 can be driven to move up and down along with the up and down movement of the top column 3; the support table 4 is used for bearing the graphite heater 5 and the crucible 6; the graphite heater 5 has a heating function on the crucible 6 in the graphite heater, so that the polycrystalline silicon material in the crucible 6 is heated and melted; the crucible 6 is used for containing polycrystalline silicon materials and is used as a place for single crystal hot melting and growth; the fixed column 7 is used for fixing the seed crystal 8 and suspending the seed crystal above the crucible 6, when the materials in the crucible 6 are melted completely, the crucible 6 is driven to ascend, the lower end of the seed crystal 8 is immersed in the materials, then the crucible 6 is driven to descend, the materials are far away from the seed crystal 8, and the materials grow along the lower end of the seed crystal 8 in the process; the pillar 10 is used for bearing the base cylinder 9 and enabling the base cylinder 9 to be fixed below the supporting table 4, the base cylinder 9 is used for bearing the limiting ring 11, and the limiting ring 11 is used for limiting the descending position of the supporting table 4 and avoiding the descending of the supporting table from being too much.

Example 2

A reverse pull-up type single crystal furnace is shown in figures 1-3 and comprises a furnace body 1, a graphite felt 2, a top column 3, a support table 4, a graphite heater 5, a crucible 6, a fixed column 7, a seed crystal 8, a base cylinder 9, a support column 10 and a limiting ring 11, wherein the graphite felt 2 is fixedly connected to the inner wall of the furnace body 1, the top column 3 is inserted into the furnace body 1, the upper end of the top column 3 is positioned inside the furnace body 1, the lower end of the top column 3 is positioned below the furnace body 1, the lower end of the top column 3 is connected with a lifting mechanism, the support table 4 is fixedly connected to the upper end of the top column 3, the graphite heater 5 is fixedly connected to the support table 4, the crucible 6 is connected to the inside of the graphite heater 5, the fixed column 7 is fixedly connected to the upper end of the furnace body 1, the seed crystal 8 is fixedly connected to the lower end of the fixed; a base cylinder 9 is fixedly connected to the inside of the furnace body 1 through a support column 10, a limit ring 11 is fixedly connected to the bottom surface of the base cylinder 9, and the top column 3 penetrates through the limit ring 11 and the bottom surface of the base cylinder 9.

The lifting mechanism comprises an internal thread sleeve 12, a cylindrical part 13 and a motor 14, wherein an external thread part is arranged on the outer wall of the lower part of the top column 3, the internal thread sleeve 12 is connected to the external thread part of the top column 3 in a threaded manner, the cylindrical part 13 is fixedly connected to the lower end of the internal thread sleeve 12, and a main shaft of the motor 14 is in transmission connection with the cylindrical part 13. The graphite heater 5 comprises a U-shaped metal plate 15, an annular hoop 16 and electrodes 17, wherein the U-shaped metal plate 15 is provided with a plurality of U-shaped metal plates 15, the U-shaped metal plates 15 are enclosed into a cylinder, the annular hoop 16 is fixedly connected to the side wall of the cylinder, and the two ends of the U-shaped metal plates 15 are respectively connected with the electrodes 17. The fixed column 7 and the seed crystal 8 are both in a cylindrical shape, the axes of the fixed column 7 and the seed crystal 8 are mutually overlapped, and the lower end of the seed crystal 8 is provided with a conical surface. The axis of the top column 3 is superposed with the axis of the furnace body 1; the diameter of the inner edge of the limiting ring 11 is smaller than that of the outer edge of the support table 4.

In the above technical solution, the internal thread sleeve 12 is screwed with the lower portion of the top pillar 3, and the cylindrical portion 13 fixed to the internal thread sleeve 12 is used for establishing a transmission connection relationship with the motor 14, the transmission connection relationship may be that the main shaft of the motor 14 directly drives the cylindrical portion 13 through a coupler, or may be a conventional transmission mode such as gear transmission, when the motor 14 drives the cylindrical portion 13 to rotate, the cylindrical portion 13 drives the internal thread sleeve 12 to rotate therewith, based on the screwing relationship between the internal thread sleeve 12 and the top pillar 3, when the internal thread sleeve 12 and the top pillar 3 rotate relatively, the internal thread sleeve 12 and the top pillar 3 simultaneously perform relative translation (i.e. a lead screw principle), so as to drive the top pillar 3 to lift.

Furthermore, the present embodiment also provides an alternative configuration of the graphite heater 5: the U-shaped metal plate 15 is used for enclosing a cylinder shape so as to bear the crucible 6, the electrodes 17 at two ends of the U-shaped metal plate 15 play an electric heating role, and the annular hoop 16 positioned at the periphery of the cylinder shape is used for connecting the U-shaped metal plates 15 so as to ensure the stability of the cylinder shape.

The embodiments of the present invention have been described in detail, but the description is only for the preferred embodiments of the present invention, and is not intended to limit the present invention. Any modification, equivalent replacement, and improvement made within the scope of the present invention should be included in the protection scope of the present invention.

Claims

1. A reverse pull-up type single crystal furnace is characterized by comprising a furnace body (1), a graphite felt (2), a top column (3), a supporting platform (4), a graphite heater (5), a crucible (6), a fixed column (7), seed crystals (8), a base barrel (9), a support column (10) and a limiting ring (11), wherein the graphite felt (2) is fixedly connected to the inner wall of the furnace body (1), the top column (3) is inserted in the furnace body (1), the upper end of the top column (3) is positioned in the furnace body (1), the lower end of the top column (3) is positioned below the furnace body (1), the lower end of the top column (3) is connected with a lifting mechanism, the supporting platform (4) is fixedly connected to the upper end of the top column (3), the graphite heater (5) is fixedly connected to the supporting platform (4), the crucible (6) is connected to the interior of the graphite heater (5), the fixed column (7) is fixedly connected to the upper end of the furnace body (1), the lower end of the fixed column (7) is fixedly connected with a seed crystal (8), and the lower end of the seed crystal (8) is positioned in the crucible (6); a base cylinder (9) is fixedly connected inside the furnace body (1) through a support column (10), a limiting ring (11) is fixedly connected to the bottom surface of the base cylinder (9), and the top column (3) penetrates through the limiting ring (11) and the bottom surface of the base cylinder (9).

2. The reverse pull-type single crystal growing furnace according to claim 1, wherein the elevating mechanism comprises an internally threaded sleeve (12), a cylindrical portion (13), and a motor (14), wherein the externally threaded portion is provided on the outer wall of the lower portion of the top post (3), the internally threaded sleeve (12) is screwed to the externally threaded portion of the top post (3), the cylindrical portion (13) is fixedly connected to the lower end of the internally threaded sleeve (12), and the main shaft of the motor (14) is drivingly connected to the cylindrical portion (13).

3. The reverse pull-up type single crystal furnace according to claim 1, wherein the graphite heater (5) comprises a plurality of U-shaped metal plates (15), an annular hoop (16) and electrodes (17), wherein the number of the U-shaped metal plates (15) is several, the U-shaped metal plates (15) are enclosed into a cylindrical shape, the annular hoop (16) is fixedly connected to the side wall of the cylindrical shape, and the electrodes (17) are respectively connected to both ends of the U-shaped metal plates (15).

4. The reverse pull-up type single crystal furnace according to claim 1, wherein the fixed column (7) and the seed crystal (8) are both in a cylindrical shape, the axes of the fixed column (7) and the seed crystal (8) are coincident with each other, and the lower end of the seed crystal (8) has a conical surface.

5. The reverse pull-up type single crystal furnace according to claim 1, wherein the axis of the top pillar (3) and the axis of the furnace body (1) coincide with each other; the diameter of the inner edge of the limiting ring (11) is smaller than that of the outer edge of the supporting platform (4).